let Tween = class Tween {
	static Linear = function(t, b, c, d) {
		return c * t / d + b;
	};
	static Quad = {
		easeIn: function(t, b, c, d) {
			return c * (t /= d) * t + b;
		},
		easeOut: function(t, b, c, d) {
			return -c * (t /= d) * (t - 2) + b;
		},
		easeInOut: function(t, b, c, d) {
			if ((t /= d / 2) < 1) return c / 2 * t * t + b;
			return -c / 2 * ((--t) * (t - 2) - 1) + b;
		}
	};
	static Cubic = {
		easeIn: function(t, b, c, d) {
			return c * (t /= d) * t * t + b;
		},
		easeOut: function(t, b, c, d) {
			return c * ((t = t / d - 1) * t * t + 1) + b;
		},
		easeInOut: function(t, b, c, d) {
			if ((t /= d / 2) < 1) return c / 2 * t * t * t + b;
			return c / 2 * ((t -= 2) * t * t + 2) + b;
		}
	};
	static Quart = {
		easeIn: function(t, b, c, d) {
			return c * (t /= d) * t * t * t + b;
		},
		easeOut: function(t, b, c, d) {
			return -c * ((t = t / d - 1) * t * t * t - 1) + b;
		},
		easeInOut: function(t, b, c, d) {
			if ((t /= d / 2) < 1) return c / 2 * t * t * t * t + b;
			return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
		}
	};
	static Quint = {
		easeIn: function(t, b, c, d) {
			return c * (t /= d) * t * t * t * t + b;
		},
		easeOut: function(t, b, c, d) {
			return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
		},
		easeInOut: function(t, b, c, d) {
			if ((t /= d / 2) < 1) return c / 2 * t * t * t * t * t + b;
			return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
		}
	};
	static Sine = {
		easeIn: function(t, b, c, d) {
			return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
		},
		easeOut: function(t, b, c, d) {
			return c * Math.sin(t / d * (Math.PI / 2)) + b;
		},
		easeInOut: function(t, b, c, d) {
			return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
		}
	};
	static Expo = {
		easeIn: function(t, b, c, d) {
			return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
		},
		easeOut: function(t, b, c, d) {
			return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
		},
		easeInOut: function(t, b, c, d) {
			if (t == 0) return b;
			if (t == d) return b + c;
			if ((t /= d / 2) < 1) return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
			return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
		}
	};
	static Circ = {
		easeIn: function(t, b, c, d) {
			return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
		},
		easeOut: function(t, b, c, d) {
			return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
		},
		easeInOut: function(t, b, c, d) {
			if ((t /= d / 2) < 1) return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
			return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
		}
	};
	static Elastic = {
		easeIn: function(t, b, c, d, a, p) {
			if (t == 0) return b;
			if ((t /= d) == 1) return b + c;
			if (!p) p = d * .3;
			if (!a || a < Math.abs(c)) {
				a = c;
				var s = p / 4;
			} else var s = p / (2 * Math.PI) * Math.asin(c / a);
			return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
		},
		easeOut: function(t, b, c, d, a, p) {
			if (t == 0) return b;
			if ((t /= d) == 1) return b + c;
			if (!p) p = d * .3;
			if (!a || a < Math.abs(c)) {
				a = c;
				var s = p / 4;
			} else var s = p / (2 * Math.PI) * Math.asin(c / a);
			return (a * Math.pow(2, -10 * t) * Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b);
		},
		easeInOut: function(t, b, c, d, a, p) {
			if (t == 0) return b;
			if ((t /= d / 2) == 2) return b + c;
			if (!p) p = d * (.3 * 1.5);
			if (!a || a < Math.abs(c)) {
				a = c;
				var s = p / 4;
			} else var s = p / (2 * Math.PI) * Math.asin(c / a);
			if (t < 1) return -.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) /
				p)) + b;
			return a * Math.pow(2, -10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p) * .5 + c + b;
		}
	};
	static Back = {
		easeIn: function(t, b, c, d, s) {
			if (s == undefined) s = 1.70158;
			return c * (t /= d) * t * ((s + 1) * t - s) + b;
		},
		easeOut: function(t, b, c, d, s) {
			if (s == undefined) s = 1.70158;
			return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
		},
		easeInOut: function(t, b, c, d, s) {
			if (s == undefined) s = 1.70158;
			if ((t /= d / 2) < 1) return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
			return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
		}
	};
	static Bounce = {
		easeIn: function(t, b, c, d) {
			return c - Tween.Bounce.easeOut(d - t, 0, c, d) + b;
		},
		easeOut: function(t, b, c, d) {
			if ((t /= d) < (1 / 2.75)) {
				return c * (7.5625 * t * t) + b;
			} else if (t < (2 / 2.75)) {
				return c * (7.5625 * (t -= (1.5 / 2.75)) * t + .75) + b;
			} else if (t < (2.5 / 2.75)) {
				return c * (7.5625 * (t -= (2.25 / 2.75)) * t + .9375) + b;
			} else {
				return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b;
			}
		},
		easeInOut: function(t, b, c, d) {
			if (t < d / 2) return Tween.Bounce.easeIn(t * 2, 0, c, d) * .5 + b;
			else return Tween.Bounce.easeOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
		}
	};
};

export {
	Tween
}
